1. Field of the Invention
This invention relates to a container for a layered chemical analysis system utilizing a plurality of layers of material which must be confined in intimate contact with each other in order to effectively perform the analysis.
2. Description of the Prior Art
Layerd chemical analysis systems of various types have been well known for some time. Typical of such analysis systems are those disclosed in U.S. Pat. Nos. 3,723,064 (Liotta); 4,356,149 (Kitajima et al.); and 4,258,001 (Pierce et al.); EPO Application No. 51,183, Published May 12, 1982 (Akiyoshi), and British Pat. No. 2,111,676 (Liotta). Such analysis systems typically include a layered stack of materials which may be impregnated with various chemical reagents necessary to carry out the desired sequence of reactions. The typical mode of use is to deposit a sample under test onto a layer of the stack and to permit that sample to pass through or into the layers. The existence of a constituent of interest in the sample is typically denoted by the presence or absence of a predetermined indication, for example, the appearance of a colored reaction product.
It has been noted that sample passage through the layers in such analysis systems can be virtually nonexistent or inconsistent unless the layers of the stack are in intimate contact with each other. To provide such contact, in some analysis systems the layered stack of materials is held together by applying adhesive circumferentially about its edge, or by adhering the layers to each other by adhesive disposed therebetween. However, the former expedient may not maintain the layers in the necessary intimate contact, while with the latter, the adhesive must be porous and not interactive with the sample, and the layers will not be readily separable. Moreover, each expedient requires added manufacturing steps.
As an alternative a stretch/shrink filament or film could be utilized to hold together the layered stack of materials. However, this is basically a variation of circumferential banding of the stack and would not appear to supply the required normal force to hold the layers in intimate contact due to the mechanics of the geometry of the stack.
In view of the foregoing, therefore, it is believed advantageous to provide a container for a layered chemical analysis system which exerts the required compressive force in a direction normal to the layered stack of materials to compress the same into intimate contact with each other. Further, it is believed advantageous to provide a container arrangement which permits access to both the upper and lower layers in the stack. Such access may be desirable, for example, respectively to permit deposition thereon of the sample under test or to view the indication produced by the sample. Yet further, it would be advantageous to provide a container which is adapted to provide a predetermined multiplicity of test sites, with each test site in a container having substantially the same magnitude of normally directed compressive force exerted on the layered stack. Still further advantage is believed provided if each of a plurality of containers can be assured to provide compressive forces of substantially equal magnitude on the layered stacks therein. Yet further, it is believed advantageous to provide a container which is easy to assemble and use and which has members which occupy a first position relative to each other to receive and hold the layers of the stack and thereafter move with respect to each other into closed contact to exert the requisite normal force on the layered stack.